The GAIN a domain of alpha-helices and beta-strands that is found in cell-adhesion GPCRs and precedes the GPS motif where the autoproteolysis occurs, family, Pfam:PF01825. The full GAIN domain, comprises the GPS and the GAIN, in cell-adhesion GPCRs, and is the functional unit for autoproteolysis. The GPS motif at the end of the GAIN domain is an ancient domain that exists in primitive ancestor organisms, and the full GAIN + GPS is conserved in all cell-adhesion GPCRs and all PKD1-related proteins [1].

1: A novel evolutionarily conserved domain of cell-adhesion GPCRs mediates autoproteolysis. Arac D, Boucard AA, Bolliger MF, Nguyen J, Soltis SM, Sudhof TC, Brunger AT; EMBO J. 2012;31:1364-1378. PMID:22333914